An LED traffic signal typically includes a housing having a printed circuit board with a plurality of LEDs disposed thereon. A single large front cover is connected to the housing, facing the user. The front cover serves to create a light emitting surface and can act as a color filter and a lens to direct the light towards the user. The front cover also provides the outer appearance of the LED traffic signal.
Some concerns with the front cover are the undesirable effects of sun phantom where the traffic signal can appear to be in an on-state even when the traffic signal is in an off-state, due to the sun rays reflecting the traffic signal.